Before determining which tax forms you should file, you should know what each form is. Basically, there are two main forms which a nonresident may be required to file such as form 8843 and/or 1040-NR.
Tax form 8843
Form 8843 is a statement filed by all nonresidents. It is for informational purposes only and does not report a person’s income. Nonresidents who did not make any income in the U.S. are required to file this form by itself. If you want to file this form on your own, you can file it here.
Tax form 1040NR
Form 1040NR is the IRS income tax return for nonresidents who are reporting the income (money from your job or RA program) made in the tax year, claiming dependents, reporting business income or investment income. If you are reporting any of the income mentioned or claiming dependents, you must file this form along with form 8843. You can file both forms here only in the event you are not claiming dependents or income above $40,125 for the year.